[cmake-developers] -DCMAKE_OSX_DEPLOYMENT_TARGET:STRING="" -DCMAKE_OSX_SYSROOT:STRING=/ broken in 3.7.0-rc2

[Jack Howarth]

Gregor,
     While I still think your hack to obtain the versioned SDK is
wrong because it relies on passing invalid arguments to 'xcodebuild
-sdk', the following change restores the expected behavior for
-DCMAKE_OSX_DEPLOYMENT_TARGET:STRING="" -DCMAKE_OSX_SYSROOT:STRING=/
while allowing your hack to function when
-DCMAKE_OSX_DEPLOYMENT_TARGET is not an empty string...

--- cmake-3.7.0-rc2/Modules/Platform/Darwin-Initialize.cmake.orig
2016-10-30 09:45:46.000000000 -0400
+++ cmake-3.7.0-rc2/Modules/Platform/Darwin-Initialize.cmake
2016-10-30 15:16:57.000000000 -0400
@@ -116,7 +116,7 @@
 set(_CMAKE_OSX_SYSROOT_ORIG "${CMAKE_OSX_SYSROOT}")
 set(_CMAKE_OSX_SYSROOT_PATH "")
 if(CMAKE_OSX_SYSROOT)
-  if("x${CMAKE_OSX_SYSROOT}" MATCHES "/")
+  if("x${CMAKE_OSX_SYSROOT}" MATCHES "/" AND
CMAKE_OSX_DEPLOYMENT_TARGET MATCHES "")
     # This is a path to the SDK.  Make sure it exists.
     if(NOT IS_DIRECTORY "${CMAKE_OSX_SYSROOT}")
       message(WARNING "Ignoring CMAKE_OSX_SYSROOT value:\n
${CMAKE_OSX_SYSROOT}\n"
@@ -125,10 +125,8 @@
       set(_CMAKE_OSX_SYSROOT_ORIG "")
     endif()
     set(_CMAKE_OSX_SYSROOT_PATH "${CMAKE_OSX_SYSROOT}")
-  endif()
-
-  if(CMAKE_OSX_SYSROOT)
-    # Transform the (maybe unversioned) sysroot into a versioned path.
+  else()
+    # Transform the sdk name into a path.
     execute_process(
       COMMAND xcodebuild -sdk ${CMAKE_OSX_SYSROOT} -version Path
       OUTPUT_VARIABLE _stdout

    Jack

On Sun, Oct 30, 2016 at 2:53 PM, Jack Howarth
<howarth.mailing.lists at gmail.com> wrote:
> Gregor,
>      The change in
> https://cmake.org/gitweb?p=cmake.git;a=patch;h=540815eec2b83a8b43689580c54e8950d9f5868b
> is logically flawed because it allows...
>
> COMMAND xcodebuild -sdk ${CMAKE_OSX_SYSROOT} -version Path
>
> to be passed ${CMAKE_OSX_SYSROOT} containing "/" which isn't a valid
> argument for 'xcodebuild -sdk'...
>
> $ xcodebuild -sdk /
> Build settings from command line:
>     SDKROOT = macosx10.12
>
> This erroneously returns macosx10.12 despite the Xcode 7.3.1 Command
> Line Tools being installed in / containing the 10.11 SDK files.
>              Jack
>
>
> On Sun, Oct 30, 2016 at 2:04 PM, Jack Howarth
> <howarth.mailing.lists at gmail.com> wrote:
>> Gregor,
>>         This is also a severe regression because if forces the cmake
>> users to build against the 10.12 SDK on 10.11 which is not well tested
>> for backward compatibility on 10.11. Your change makes it impossible
>> to build against the SDK in / installed by the Xcode Command Line
>> Tools package.
>>                Jack
>>
>> On Sun, Oct 30, 2016 at 1:33 PM, Jack Howarth
>> <howarth.mailing.lists at gmail.com> wrote:
>>> Gregor,
>>>       Your commit of...
>>>
>>> https://cmake.org/gitweb?p=cmake.git;a=log;h=540815eec2b83a8b43689580c54e8950d9f5868b
>>>
>>> has caused a major regression in cmake 3.7.0 as it no longer properly
>>> honors the combination...
>>>
>>> -DCMAKE_OSX_DEPLOYMENT_TARGET:STRING="" -DCMAKE_OSX_SYSROOT:STRING=/
>>>
>>> This is obvious by simple inspection of the code in
>>> Modules/Platform/Darwin-Initialize.cmake as
>>> the code no longer honors  -DCMAKE_OSX_SYSROOT:STRING=/. At the very
>>> least, this code
>>> needs to be modified to have cmake emit "-isysroot /" in that case.
>>>        IMHO, this issue should be considered a blocker for the cmake
>>> 3,7.0 release on darwin.
>>>                       Jack
>>>
>>>
>>> On Sun, Oct 30, 2016 at 9:36 AM, Jack Howarth
>>> <howarth.mailing.lists at gmail.com> wrote:
>>>> The change...
>>>>
>>>> --- cmake-3.6.2/Modules/Platform/Darwin-Initialize.cmake 2016-09-07
>>>> 10:11:58.000000000 -0400
>>>> +++ cmake-3.7.0-rc2/Modules/Platform/Darwin-Initialize.cmake
>>>> 2016-10-19 09:47:45.000000000 -0400
>>>> @@ -125,8 +125,10 @@
>>>>        set(_CMAKE_OSX_SYSROOT_ORIG "")
>>>>      endif()
>>>>      set(_CMAKE_OSX_SYSROOT_PATH "${CMAKE_OSX_SYSROOT}")
>>>> -  else()
>>>> -    # Transform the sdk name into a path.
>>>> +  endif()
>>>> +
>>>> +  if(CMAKE_OSX_SYSROOT)
>>>> +    # Transform the (maybe unversioned) sysroot into a versioned path.
>>>>      execute_process(
>>>>        COMMAND xcodebuild -sdk ${CMAKE_OSX_SYSROOT} -version Path
>>>>        OUTPUT_VARIABLE _stdout
>>>>
>>>> is an obvious mistake in cmake 3.7.0-rc2. The removal of the 'else()'
>>>> statement here and the substitution of the ' if(CMAKE_OSX_SYSROOT)'
>>>> defeats the prior handling of 'if("x${CMAKE_OSX_SYSROOT}" MATCHES
>>>> "/")'. This causes '-DCMAKE_OSX_DEPLOYMENT_TARGET:STRING=""
>>>> -DCMAKE_OSX_SYSROOT:STRING=/' to not be honored and -isysroot to be
>>>> emitted as a compiler flag universally.
>>>>
>>>> https://gitlab.kitware.com/cmake/cmake/issues/16394